Negatively and positively charged excitons are identified in the spatially-resolved photoluminescence spectra of quantum wires. We demonstrate that charged excitons are weakly localized in disordered quantum wires. As a consequence, the enhancement of the "binding energy" of a charged exciton is caused, for a significant part, by the recoil energy transferred to the remaining charged carrier during its radiative recombination. We discover that the Coulomb correlation energy is not the sole origin of the "binding energy", in contrast to charged excitons confined in quantum dots.

Influence of long-range substrate roughness on disorder in V-groove quantum wire structures Effect of indium segregation on optical properties of V-groove InGaAs/GaAs strained quantum wires Appl. Phys. Lett. 75, 3300 (1999); 10.1063/1.125331 Two-dimensional quantum-confined Stark effect in V-groove quantum wires: Excited state spectroscopy and theory Appl.Selective carrier injection into V-groove quantum wires

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We report on the observation of negatively and positively charged excitons in the photoluminescence spectra of V-groove quantum wires. The charged exciton binding energy increases with the strength of the quantum confinement. We demonstrate that the charged excitons are localized by the fluctuations of the confinement potential and estimate a minimal value of the localization length.Introduction Observation of charged excitons in the photoluminescence (PL) spectra of semiconductor quantum wires has until recently been hindered by inhomogeneous line broadening due to structural imperfections in high quality samples. A negatively charged exciton (X -) with a binding energy of 2.3 meV relative to the exciton line was identified, however, in a micro-photoluminescence study of a T-shaped QWR of improved quality [1]. This observation was made possible by the reduction of the PL linewidth to about 1 meV.In this paper we study the PL spectra of n-type modulation-doped and undoped GaAs/AlGaAs V-groove quantum wires (QWRs), in which the carrier density was tuned by applying a potential on a Schottky gate. In order to free oneself from the inhomogeneities of the wires, which are present on a length scale of 1 to 10 µm, we prepared samples with submicron apertures made through an opaque Aluminium film. Previous optical studies that were performed with this technique on similar and undoped QWR samples have evidenced sharp PL lines with about 140 µeV linewidth [2]. These spectral lines were ascribed to excitons recombining in the local potential minima created by structural disorder at the interface.

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